I cannot speak specifically to the Lumin, but my experience has been that double the cost and typically you get a large improvement in sound quality assuming the rest of your system is of similar or greater quality. Lumin is well regarded. It is extremely unlikely they would have two models without commiserate sound quality differences. If they did the forums and reviews would point it out.
I have experience with streamers at the $1K, $2K, $3K, $5K, $10K, and the most impressive streamer I have ever heard which has the same sound quality of my excellent analog rig the Aurrender W20SE… ($22K) I found the latter to be a bargain in terms of sound quality.. altough it is the most expensive component. You can see my systems under my ID.